A cosmid containing the human NKG2A gene was isolated. The gene was partially sequenced, revealing 7 exons, including one 5' untranslated exon. The 54 base pair exon 5 was missing in the published cDNA clone NKG2B, consistent with the existence of different splicing. This was confirmed by reverse transcription-polymerase chain reaction of total RNA from normal lymphocytes. The NKG2A gene was mapped by FISH to chromosome 12p12.3-p13.1 in proximity to the CD69 and Prp genes. These data support the presence of a human lectin-like NK gene complex, analogous to the NK complex on mouse chromosome 6.